Process of purifying clay, &amp;c.



UNTTED- PATENT GFFTCE.

HER-MANN GRUBER, F LEIPZIG-PLAGW'ITZ, GERIYKANY, ASSIGNOR OF ONE-HALF TO .FIRITZ SCHULZ JUN. AKIIENGESELLSCHAFT, OF LEIPZIG, GER-MZANY, A CORPORA- TION OF GER-MANY.

PROCESS OF PURIFYING CLAY, 85c.

E0 Drawing.

To all whom it may concern Be it known that I, HERMAXN GRUBER, a citizen of the Empire of Germany, and a resident of Leipzig-Plagwitz, Kingdom of Saxony, Germany, have invented certain new and useful Improvements in Processes of Freeing Aluminum Silicates, Kaolin, and the Like from Iron, of which the following is a specification.

This invention has reference to a novel process of freeing aluminum silicates, kaolin and the like from iron.

The silicates of aluminum, kaolin and like materials are found in nature in a rather impure state and contain larger or smaller quantities of iron compounds particularly iron OXlClS. It is known that such raw products may be freed fromiron compounds by means of. mineral acids such as hydrochloric acid. sulfuric acid or sulfurous acid Such method is impractical 1n scTfiTf' as it requires large quantities of acid which mustbe washed out when the process is fin-. ished and heat is a l app/li ed during the carrying out off 'sEine For the above reasons these" methods are not applicable for practical purposes and merely inferior materials of relatively low value are to be treated thereby which do not allow of employing methods incurring considerable eX- pense or involving arduous labor.

29 ..-nracessmicneingjhs-subjectmatter 9f this ijt QiiQIl overcomes the described deficiencies and is carried out at relatively low cost, in ashort time, and with;.. out the application of heat. According to my novel process the raw material containing iron as an impurity is first stirred into Water to which but a small quantity of mineral acid has been added and then hydrosulfurous acid or its salts are added in a small quantity a-t-ordinary temperature.

To free clay, for instance from the iron contained therein the raw material is stirred into twice its weight of Water which. has been acidulated by some mineral acid and then a small quantityof hydrosulfurous acid or its salts is added. i

In order to purify 100 kilos of silicate of aluminum, for instance, same are stirred into 200 kilos of Water containing 200 grams of concentrated sulfuric acid of 66 B. and

Specification of Letters Patent. Applicatipn filed September 7, 1911. Serial No. 648,240.

Patented Aug. 2'2, 1912-.

200 grams of sodium hydrosulfite. In the course of about hour a raw material'is obtained which is completely free from iron. When the purified material has settled. the liquid above same, which consists princi pally of avery dilute solution of sulfate of iron, may beeasily decanted withoutloss of purified material. The reaction takes place according to the following equation:

The hydrosulfurous acid or compound or salt reduces the triatomic iron to diatomic iron. At the same time the hydrosulfite is oxidized to a sulfurous compound, for instance according to the equation:

The iron sultite is transformed in the presence of sulfuric acid into, sulfate and the sulfurous acid set at liberty acts again in smtu 'nascendi on more of iron oxid as a reducing and dissolving agent. This is repeated until, at the end of the reaction, all iron has been transformed into sulfate.

I claim as my invention:

1. The process of freeing aluminum silicates, kaolin and like products from iron consisting in subjecting said products at ordinary temperature to the action of a small quantity of a hydrosulfurous compound in the presence of acidulated water.

2. The process of freeing aluminum silicates, kaolin and like products from iron consisting in subjecting said products atordinary temperature to the action of a small quantity of a hydrosulfite in the pres- .ence of acidulated water.

3. The process of freeing aluminum silicates, kaolin and like products from iron consisting in subjecting said products at ordinary temperature to the action of a small quantity of sodium 'hydrosulfite in the silicates, kaolin and the like from iron con- I Signed at Leipzig, Germany, this 23rd sisting of stirring 100 kilos of the material day of August 1911. lnto 200 kilos of Water containing 800 grams of concentrated sulfuric acid and aading HERMABL GRL'BLR' :3 5200 grams of sodium hydrosulfite, allowing Witnesses:

the mass to settle and decanting the liquid R. VVESTACOTT,

above same.

E. J. Snroxns. 

